1. Field of the Invention
In the handling of chemicals and other dangerous substances, it is desirable to use special rubber gloves which are manufactured without imperfections. The present invention provides a means for forming a mold which is usable to form such gloves thereon.
It is usual that ceramic molds are used as the form about which the rubber is placed for making these high quality gloves. The present composition is usable as a glaze about the external surface of such a ceramic mold which glaze itself is electrically conductive to facilitate the monitoring for imperfections of the gloves formed thereon. Also the conductive surface serves to increase the flow of heat to the glove to facilitate curing thereof.
In practice a glove will be formed about a ceramic mold having the conductive glaze of the present invention therearound. And then prior to removal of the glove from the form, the form and the glove as a unit may be dipped in an electrolytic solution such that the conductive glaze itself will act as one electrode and another electrode may be placed in the electrolyte. In another method the glove need not be dipped in an electrolytic solution, but an electrode may be manually or otherwise caused to pass over the surface of the glove and visual arcing or a surge reading on a voltage or current meter will indicate an imperfection. In either system application of a voltage difference across the two electrodes will cause electrical current to flow between the electrodes only if an imperfection exists in the wall of the gloves at any point such that electric current may flow therethrough. However if the glove is indeed a perfect glove having no apertures therethrough or pinholes the flow of current between the electrodes will be prevented. In this manner a glove can be tested for imperfections in a one-step process without requiring the removal of the glove from the mold form and the placing of the glove in a special test apparatus.
2. Description of the Prior Art
The main problem existing in the prior art in the forming of electrically conductive glazes for ceramic mold forms has been the lack of consistency of resistivity between one fired glaze and the next fired glaze. It is desirable to use a ceramic glaze having repeatably consistent surface resistivity. The prior art conductive glazes did not have this quality but the glaze as disclosed and claimed in the present invention provides a simple formula for forming the glaze and, most importantly, provides a repetitive consistency of the surface resistivity of the glaze in the range of 50,000 ohms to 150,000 ohms when the measurement is made at points 1 and 2 inches apart.
Also the components of the glaze of the present invention are reasonable inexpensive as well as easily accessible and in this manner provides further advantages over conductive glazes of the prior art.
Most prior art conductive surfaces on molds are achieved by using electrically conductive coatings rather than using the ceramic itself as the conducting agent. Conductive coatings tend to wear off quickly when not using the present invention but a conductive ceramic glaze has a very extended useful lifetime.